Effect of basic fibroblast growth factor (bFGF) on interleukin-6 (IL-6) secretion by bone marrow stromal cells from myeloma patients (MM-BMSCs).
(A) Time-course experiments: IL-6 concentrations were determined in serum-free culture supernatants of MM-BMSCs exposed to (▪) 10 ng/mL of bFGF for 12, 24, and 72 hours; (○), unstimulated controls. IL-6 concentrations were corrected for 105 cells. Data represent median values and interquartile ranges of 7 independent experiments in different MM-BMSC cultures. The Kruskal-Wallis test and the multiple comparisons' criterion were used to identify differences between groups (10 ng/mL vs controls, P = .05 at 12 hours;P = .001 at 24 hours; P = .0001 at 72 hours). (B) Dose-response effects: IL-6 concentrations were determined in 13 independent MM-BMSC cultures stimulated with 1, 5, or 10 ng/mL of bFGF for 72 hours (■). As a control experiment, stimulation with 10 ng/mL of bFGF was also performed in the presence of polyclonal antihuman bFGF neutralizing antibody (anti-bFGF, 40 μg/mL) in serum-free conditions (▪). IL-6 concentrations are corrected for 105 cells. Data represent median values and interquartile ranges (IQRs). The Mann-Whitney rank sum test was used to identify differences between groups (10 ng/mL bFGF vs controls, P < .001; 10 ng/mL bFGF vs 10 ng/mL bFGF + anti-bFGF, P = .01).
